So-called twisted conductors, insulated with paper and with conductor elements composed of wires for electrical appliances that are operated in oil are known, in which the wires of the conductor elements are lacquered. By way of example, polyvinylacetal is used as a lacquer, and like other lacquers contains large amounts of solvent. A lacquer such as this is applied in a plurality of layers to the wire. It must then be burned in a special oven, during which process the solvent must be removed at the same time, in an environmentally friendly form. By way of example, DE-PS 1 242 511 describes one oven which can be used for this purpose. The application of the lacquer with the subsequent processes of burning in and solvent removal is complex, and is restricted to wires with relatively small dimensions.
By way of example, a wire as described initially is used as a flat wire with a rectangular cross section in order to produce windings for transformers and electrical machines. According to the prior art, which has been known very many years, the wire is surrounded by a layer composed of paper as insulation, which is also used as a spacer from adjacent turns of the wire arranged in a winding. The production of a wire such as this and of a winding manufactured from it is considerably simpler than the wire described above. However, in practice, it has been found that a wire such as this is not corrosion-resistant in the long term. In fact, conductive copper sulphide is formed by corrosive components of the oil used as coolant during use of an electrical appliance equipped with a wire such as this, damaging the layer composed of paper. A correspondingly constructed winding then rapidly becomes unusable, so that the associated appliance no longer operates.